Y chromosome challenges decay theory, according to ScienceNOW 13 January 2010 and Nature, vol. 463, p536, 28 January 2010. The Y chromosome is the male sex determining chromosome, and because it is a very small chromosome with not many genes apart from those involved in male reproductive functions, evolutionary biologists believe its small size is the result of a long period of genetic decay and gene loss. According to this theory human and chimp Y chromosomes should be very similar as humans and chimps are supposed to share a long evolutionary history with only a brief period of evolutionary separation from a common ancestor.

A group of researchers from various American universities and the Academic Medical Centre, Amsterdam, The Netherlands, have sequenced the chimp Y chromosome and compared it to the human Y chromosome, and made a careful study of the male determining part of the chromosome, known as the MSY region. They found that “Contrary to the decelerating decay theory, the chimpanzee and human MSYs differ markedly in sequence structure.”

Chimpanzees only have two-thirds of the genes present in the human MSY but chimps had other sequences not found in humans. Because humans and chimps are believe to be 98% overall the same genetically, the researchers wrote: “We conclude that, since the separation of the chimpanzee and human lineages, sequence gain and loss have been far more concentrated in the MSY than in the balance of the genome. Moreover, the MSY sequences retained in both lineages have been extraordinarily subject to rearrangement: whole-chromosome dot-plot comparison of chimpanzee and human MSYs shows marked differences in gross structure which contrasts starkly with chromosome 21, the only other chromosome comprehensively mapped and sequenced in both species. Contrary to the decelerating decay theory, the chimpanzee and human MSYs differ markedly in sequence structure.”

Editorial Comment: In spite of all the claims that the Y Chromosome is evolving itself out of existence, all studies of it show that it is a fully functioning chromosome, well designed to carry out its role in the genome, with built in back-up systems for maintaining the genetic information it carries. Furthermore, the differences between human and chimp chromosomes are another reminder of the falseness of the claim humans are 98% the same as chimpanzees.

The study of Chromosome 21 referred to by the researchers revealed 83% of 231 genes on the chimp chromosome would produce different amino acid sequences than their human counterparts. (See “Chimp Genes 83% Non-Human” in this Fact File) The results of these detailed chromosome studied are exactly what you would expect if the genome of each kind of living organism was created by God, who made males and females and designed them to multiply after their kind, as described in Genesis. Creation Research predicts that when each chromosome is studied in detail more differences will be found, especially as we learn about the way genes are turned on and off, which is just as important for body structure and function as the genes themselves. (Ref. genetics, ape, sex, gender, prediction)

Evidence News, 28 April 2010